1. Field of the Invention
The invention relates to optical fiber lines and networks and to methods of designing and making such networks and lines.
2. Discussion of the Related Art
This section introduces aspects that may be helpful, to facilitating a better understanding of the inventions. Accordingly, the statements of this section are to be read in this light. The statements of this section are not to be understood as admissions about what is in the prior art or what is not in the prior art.
In optical fiber communications systems, non linear optical effects can distort streams of optical signals or pulses in a manner that increases the bit-error-rates (BERs) associated with demodulating data from said streams in optical receivers. To reduce such distortions of optical data streams, some optical fiber transmission systems actively manage the cumulative dispersion of the optical pulses or signals along the optical fiber transmission line therein. To produce such active dispersion management, the individual optical fiber spans of the line are typically constructed with an optical dispersion compensator at one end thereof. The optical dispersion compensator resets the cumulative dispersions of received optical signals or pulses so that the cumulative dispersions evolve along a preselected dispersion map in the optical fiber transmission line. For a proper dispersion map, such dispersion management can significantly reduce the accumulation of the unwanted distortions that nonlinear optical effects produce. In turn, this reduction can lower BERs in the optical receiver and/or increase the maximum length obtainable for the optical fiber transmission line.
In some fiber optical communications systems, different point-to-point optical paths share optical fiber spans therein. For example, an optical fiber communication system with a ring topology and more than two nodes may include optical paths with overlapping or shared optical fiber spans.